Removal and factors influencing removal of sulfonamides and trimethoprim from domestic sewage in constructed wetlands

Twelve pilot-scale constructed wetlands with different configurations were set up in the field to evaluate the removal and factors that influence removal of sulfonamides (sulfadiazine, sulfapyridine, sulfacetamide, sulfamethazine and sulfamethoxazole) and trimethoprim from domestic sewage. The treatments included four flow types, three substrates, two plants and three hydraulic loading rates across two seasons (summer and winter). Most target antibiotics were efficiently removed by specific constructed wetlands; in particular, all types of constructed wetlands performed well for the degradation of sulfapyridine. Flow types were the most important influencing factor in this study, and the best removal of sulfonamides was achieved in vertical subsurface-flow constructed wetlands; however, the opposite phenomenon was found with trimethoprim. Significant relationships were observed between antibiotic degradation and higher temperature and redox potential, which indicated that microbiological pathways were the most probable degradation route for sulfonamides and trimethoprim in constructed wetlands.